Generation of coupled radio frequency orbital angular momentum beam with an optical-controlled circular antenna array

A circular antenna array (CAA) principle for generating radio frequency orbital angular momentum (RF-OAM) beams with dual-opposite-states is proposed in an optical-controlled system. At this condition, the pre-existing restrictions of antenna amount for CAA system is extended. It is worth noting that the simulative beam patterns show almost no distortion in this superposition states case. In the following control experiment, transmission characteristics, including Error Vector Magnitude (EVM), Signal to Noise Ratio (SNR) and receiving power, are all improved significantly in each proposed coupled OAM channel, compared to ones in single-state OAM beam. The EVM can be decreased from 4.82% to 4.59% in average, and the receiving power is increased by 2.7 dB at the same transmission condition, which indicates effective propagation distance can be increased.